Figure 26

FIG. 26.--Astacus fluviatilis.--A, the right antennule seen from the inner
side ( x 5); B, a portion of the exopodite enlarged; C, olfactory appendage of the
exopodite; a, front view; b, side view ( x 300);
a olfactory appendages, au, auditory sace, supposed to
be seen through the wall of the basal joint of the antennule; setae;
en, endopodite; ex, exopodite; sp, spine
of the basal joint.

[Editor's note: illustration is reproduced here
approximately twice the size of the woodcut in the book.]